list of all the little add ons or modifications

[alan m]

hi there.
i thought i would start a thread listing all the little add on design tweeks that have been tried
be it positive or negitive on the  end reult

i was thinking that someone elses failed idea might spark another idea or way of doing it that might be the next big (little in these cases usually) tweek



recatangular inlet. works great.
bell mouth outlet. shows a lot of promise
adding a little extra curve to the side of the wall just before the inlet to stop the air hitting the inlet side too steeply. seems to work well
chamfering the bottom of a thicker baffle to reduce it thickness and increase seperation
double height seperaters . starting to be built . showing promising  data
going from a top inlet to a side inlet . removes an obstical inside the seperater



i cant think of any failed ideas off hand but il add any i think of

[guy48065]

I have a question about "tweaks" or "optimization".  Phil has written that the baffle is itself a compromise intended to work well in most situations.  What little things can be changed to improve performance?  Shorter slot?  Narrower slot?  Tight inlet elbow vs. wide radius vs. maybe an angled straight pipe?

Can any generalizations be made or will it always be "change everything and see what happens"?

[alan m]

slot length is a compromise. too long and you get more air movment under the baffle (bad) and more readgitation of settled out dust (bad). if its too short  you will get lesss air movment (good) and more of the settled dust stays seperater(good ) but less of the dust can drop  freely (bad)  and posobly increase bypass(really bad)
the width of the slot .too wide and there is more chance of dust getting sucked back up. too small and the dust cant fall through it enough. if you were only using it for fine dust only then a narrow slot might help

inlet radius. i presum you mean a top inlet. a side inlet seems to bethe best improvment there

[alan m]

a few negative ones.
phil tried
bowl shaped baffle plates . he found it not efficient enough
cone baffle plates. not the most efficient shape

[retired2]

a few negative ones.
phil tried
bowl shaped baffle plates . he found it not efficient enough
cone baffle plates. not the most efficient shape

Scroll inlet did not work for Don_Z, but I don't know anything about the construction.

[bbain]

I know others have done this as well, but I aded a vacuum relief valve to my trash can top seperator so if the hose gets blocked the shopvac doesn't crush my metal trashcan.

[alan m]

did you build one or buy one.
im going to add one to my rebuild of my shop vac one. im thinking of making one out of a bolt ,spring and ruber washers.

[bbain]

I built one, short section of abs pipe, with an end cap on it, drilled 1 hole right in the middle for the bolt, and one off to the side for air.  cut a round piece of mdf to fit in the pipe, drilled a center hole for the bolt, and glued a piece of bicycle inner tube to it.  a small slit to let the bolt through, but still seal against the inside of the endcap.  put a spring onder the mdf, then a washer and nut.  The spring tension is adjusted by the nut.

[alan m]

thanks bbain.
any pics
do you ever find that it opens without a blockage

[guy48065]

My canister-type floor vac has a bypass that opens when the filter bag gets full or the hose is blocked.  It has a little reed in it that makes a harmonica sound when air goes through it.  Something like that would be good to add to a vacuum relief to alert you.  A squeaky from a dog toy perhaps?   :)

[alan m]

thats a very good idea guy.
i dont think that these relief valves would stop the sucktion . they woud only allow in a bit of air to stop the can colapsing.
if the pipe was blocked a bit the suction would still fill the pipe and make the pronlem worse.